Regulator for variable capacity compressors



P. E. KUHL REGULATOR FOR VARIABLE CAPACITY COMPRESSORS April 28, 1936.

Filed March 11, 1952 2 Sheets-Sheet 1 wijw P. E. KUHL 2,038,577

REGULATOR FOR V ARIABLE CAPACITL COMPRESSORS April 28, 1936."

2 Sheets-Sheet 2 Filed March i1, 1952 v /o/o b 7 his! ,0 y 2 .2 U I if; 1

Patented Apr, 28, 1936 UNITED STATES PATENT OFFICE REGULATOR FOR VARIABLE CAPACITY coMPnEssoRs Paul E. Kuhl, Elizabeth, N. 'J., assignor to Standard il Development Company, a corporation of Delaware This invention relates to improvements in the regulation of the suction or discharge pressure of fluid compressors.

The invention will be fully understood from the following description taken in connection with the accompanying drawings in which latter- Fig. 1 is a diagrammatic view showing the improved regulator connected to aconstant speed in variable capacity compressor of approved construction, the compressor being shown in side elevation with parts broken away.

Fig. 2 is a diagrammatic view of a stabilizer pressure controller, and

Fig. 3 is a diagrammatic view of a modified form of compressor control.

Referring particularly to Fig. 1, reference numeral designates the cylinder of a compressor pump having a piston 2 actuated by a piston rod 3. The cylinder is disposed in a tube which constitutes an intake 4 and an outlet 5. Clearance pockets 1 open into the cylinder at opposite ends of the cylinder and are governed by pocket controls 8. Valves I] control the opening of the clearance pockets into the cylinder. Each valve II is provided with a stem -|2 connecting the valve II and control piston l3 for reciprocation in the pocket and pocket control respectively. Leakage from the clearance pockets 1 to the atmosphere along the stem I2 is prevented by means of a stufling box. The pistons l3 are pneumatically or hydraulically operated by means of fluid introduced into the head of each pocket control 8 through lines |8, I9; and 2| respectively.

A multi-port distributor is provided which opens or closes the clearance pockets successively by introducing or withdrawing the control fluid uch as air or water or the like from the clearance pockets. The distributor valve includes a barrel 25. An inlet line 26 opens into one end of the barrel for introducing air or water or the like under pressure from a suitable source of pressure not shown. Preferably the fluid is introduced from line 26 under a pressure of approximately eighty pounds per square inch. Lines l8, l9, 2|) and 2| open through ports into the barrel in spaced relation at spaced intervals longitudinally of the barrel at successively progressively increasing distances from the inlet line 26. Communication of the inlet line 26 with the lines i8, l9, 20 and 2| is controlled by means of a piston 28 which is mounted for reciprocation longitudinally of the barrel. The force of a spring 38 55 normally maintains the piston 28 in retracted position whereby all of the lines l8, I9, 20 and 2| are in communication with the line 26-. This movement of the piston 28 to retracted position is partially assisted by the force of the compressed fluid entering the barrel through line 26. One end of the spring 30 is aflixed to a suitable support 3|. The other end is compressed by the.

nut 32 whichoperates on a threaded piston rod 34. The piston rod 34 is secured to the piston 28 and passes into the barrel through a vent 34', as clearly shown in Fig. 1. The opposite end of the piston rod is afflxed to a diaphragm 35.

The multi-port diaphragm valve is actuated to determine the communication between inlet 26 and the lines l8, I9, 20 and 2| by means of fluid such as air under pressure which is introduced above the diaphragm through a line 35'.irom a suitable control mechanism 36. The compressed fluid from line 35' opposes the spring 38 to reciprocate the piston 28 to open or close communi-' cation of the lines l8, I9, 20 and 2| with the line 26 as desired. The position of the piston is determined by the air pressure developed on the diaphragm by a pilot operated pressure controller 36, preferably a stabilized control instrument. The controller communicates with the line 35 as shown and with the inlet 4 of the compressor cylinder I through a line 31. Alternatively the line 31'can connect the controller with the outlet of the compressor cylinder.

The pressure controller shown in Fig. 2 comprises a tubular helical spring 38 which is connected through a tube 39 and the line 31 with the pressure which is to be controlled. Variation in the fluid pressure within the line 31 causes the tubular helical spring 38 to either contract or expand. The end of the spring 38 is connected at 40 to a link 4| which is pivotally supported by a rod 42 on theaxis of the spring. The link 4| is pivotally connected to a rod 43 which in turn is connected to a flapper 44. The flapper 44 is mounted for rotation upon a shaft 45. By this construction should the pressure being controlled rise, the helical spring 38 will expand thus moving the connecting rod 43 to the left as viewed in Fig. 2, thereby causing the flapper 44 to be moved in a clockwisedirection.

Compressed air from a line 48 is passed through the stabilizer 36 where it is delivered through a nozzle 50 in a manner to be later described, and the flow of the compressed air through the nozble is controlled by means of theflapper 44. The flapper is continuously held in a balanced position with respect to the nozzle. The variation in the obstruction to the compressed air issuing from the nozzle 50 is caused to influence a pilot valve 5| by the following arrangement of parts: A flexible conduit 52 leading from the nozzle 58 opens through one of the plates of a bellows 53. The other plate is connected to the valve stem 54 of the pilot valve control head 5|. The valve stem 54 carries a valve head 55 which is adapted to be reciprocated in a valve chamber 56 to alternatively open communication between the air inlet 48 or an air outlet 59 and the valve chamber which in turn is connected to the conduit 35'. The compressed air is preferably introduced through the line 48 under a pressure of approximately 15 pounds per square inch above atmospheric pressure. The bellows 53 is so mounted that alteration in the pressure of the fluid within the bellows with resultant collapse or expansion of the bellows causes change in position of the valve stem 54. When the instrument is in operation controllingthe pressure; the nozzle and flapper are substantially in contact. The

position of the nozzle 58 is determined by the air pressure within a line 60 which opens into the valve chamber 56 and which communicates with a chamber 6| of a sylphonbellows. A chamber 62 of another sylphon bellows communicates through a capillary tube 63 with the line 60. A disc 64 separates the chambers 6| and 62 and is connected through links 65, 66 and 61 with an arm of a bell crank 68. The other arm of the bell crank .is connected by a link 68 with the nozzle 50.

Assuming the instrument to be in operating equilibrium, the air pressure on top of the diaphragm 35, see Fig. 1, will be the same as the air pressure within the line 35', line 6!! connecting the sylphon bellows 6| to the valve chamber 56, and the sylphon bellows 62. Should the pressure being controlled rise, the helical spring 38 will expand thus moving the connecting link 43 to the left as viewed in Fig. 2 which causes the flapper 44 to be moved clockwise as viewed in Fig. 2.

Air under pressure enters the control head 5| and passes through a by-pass 10 with its restriction II and the line 52 and blows out of the nozzle 50 against the flapper 44. As the flapper 44 moves to the left it restricts the flow of air from the nozzle 50 and builds pressure within the bellows 53. The bellows 53 therefore expands thereby moving the plot valve 55 to the right, as viewed in Fig. 2, shutting off the air entering the valve chamber and permitting the air to leak away from the diaphragm valve and sylphon bellows 6| at 59. The sylphon bellows are actuated by springs, not shown, of equal strength inside the bellows. Sirrce the pressure in chamber 6| is reduced the greater pressure in chamber 62 functions to cause the disc 64 with its attached links to be moved upwardly thereby rotating the bell crank 68 counter-clockwise as viewed in Fig. 2 and in turn withdrawing the nozzle 58 to the left as viewed in Fig. 2. This produces an opposite efiect with respect to the compression of the air issuing from the nozzle 50 from that produced when the flapper is moved to the left, as viewed in Fig. 2, and thereby tends to minimize the effect of moving the flapper. The mechanism thereby seeks a balanced position.

A relationship is established between the movement of the main valve which is a function of the pressure in line "35 and the magnitude of the change in pressure in line 31 which it is desired to control. Since the sylphon 62 is 'connected to sylphon 6| through the capillary tube 63, the pressure in sylphons 6| and 62 becomes balanced at a rate depending upon the length and diameter of the capillary tube. The lever system 61, 68 and 69 is thus brought back to a mid-position. While a particular form of stabilizer pressure controller has been described, it will v be understood that other devices for this purvalves H which open when fluid pressure is applied through lines I 8, I9, 20 and 2|, and which close when air pressure thus supplied is released. Similarly a by-pass is provided from the head end to crank end which opens when air pressure is applied in line 15. It isunderstood that air pressure in line 15 could be used to operate any of the usual compressor unloaders such as bypass from suction to discharge or hold the suction valves open.

A three-way solenoid valve 11 is connected through relays to the field circuit of the motor, not shown. This valve communicates with the multi-port valve 25 and with a capacity tank 18 by means of a line 19. A valve head 80 of the solenoid valve is actuated by a solenoid 8|. The solenoid is connected to the motor circuit in the customary manner whereby on voltage clips or failure of power the solenoid 8| is de-energized thereby permitting the valve head 80 to close communication of a vent 83 with the line 19, whereby fluid such as air under pressure admitted through a line 84 rapidly enters the capacity tank 18 and clearance pocket controls 8 and by-pass valve control (not shown) thereby unloading the compressor. Upon return of voltage, or when the motor reaches synchronous speed on starting, the solenoid valve 80 is withdrawn from the vent 83 thereby releasing the fluid such as air from above the piston 28 and permitting the compressor to operate under load.

It will be understood that small tubing, orifices,

or similar devices may be inserted in the vent line 83 and air inlet lines 35 and 84 to permit in conjunction with the capacity tank the regulation of the rate at which the compressor is loaded or unloaded.

The capacity tank being large as compared with the volume of the clearance pocket controls etc.. will not aflect the speed at which the control in normal operation can open or close clearance pockets.

Fluid from the multi-port valve can be used to control devices other than a compressor such as heating devices, flow control devices, or the like, in which case a temperature controller or rate of flow controller would be substituted for the pressure controller 36.

Various changes may be made within the scope of the appended claims in which it is desired to claim all novelty inherent in the invention as broadly as the prior art permits.

I claim:

1. The combination with a gas compressor .having pressure operated control devices for controlling the unloading and loading of the compressor, of a distributor valve including a barrel having lines leading to the control devices and including a reciprocable piston controlling admission of pressure fluid to the lines and release therefrom, an inlet for introducing fluid under pressure into the barrel in spaced relation to the piston, the barrel having a vent for releasin fluid from the end of the barrel opposite the inlet, a conduit adapted to contain fluid under pressure leading to the distributor valve to actuatev the piston, and a pilot valve'having fluid communication with the gas compressor operable by fluid pressure generated by the compressor to control flow of fluid through the conduit.

2. A distributor valve, comprising a barrel having ports disposed in spaced relation longitudinally of the barrel, a piston mounted for reciprocation within the barrel to control admission to or release of fluid from the ports, an inlet for introducing fluid under pressure into the barrel in spaced relation to the piston, a flexible diaphragm associated with the piston, means for passing fluid under pressure against the diaphragm whereby the position of the piston is varied, a capacity tank communicating with the barrel on the opposite side of the piston from the inlet, and a valve controlling flow of fluid under pressure to or from the capacity tank.

3. The combination with a gas compressor having pressure operated control devices for con-- trolling the unloading and loading of the compressor, of a distributor valve including a barrel having ports disposed in spaced relation longitudinally of the barrel and communicating with successive control devices, a piston mounted for reciprocation within the barrel to control admission to and release of fluid from the ports, an inlet for introducing fluid .into the barrel in spaced relation to the piston, means for controlling the position of the piston, a capacity tank opening into the barrel on the opposite side of the piston from the inlet, a motor for actuating the compressor, an electrically operated valve connected to the electric circuit of the motor, the electrically operated valve controlling admission of fluid under pressure to the capacity tank and release therefrom.

4. A multi-port distributor valve, comprising floating reciprocable means for controlling admission to or release of fluid from the ports;

means for normally resiliently forcing said reciprocable means in one direction and means 01 low frictional and inertia values for controlling reciprocation in the opposite direction by use of fluid pressure subject to fluctuation, said fluid pressure being independent oLthe fluid passing to and from the ports. p

5. A multi-port distributor valve, comprising floating reciprocable means for controlling admission to or release of fluid from the ports, means for normally resiliently forcing said reciprocable means in one direction, fluid-pressurei opposing means attached directly to the reciprocable means adapted to withstand fluid pressure from the opposite direction ove a relatively wide area and means for mainta-inin fluid under pressure against said pressure-opposing means, whereby the position of the reciprocable means is varied according to fluctuations in the pressure of said fluid.

6. A distributor valve, comprising a plurality of ports, reciprocable means for controlling admission to or release of fluid from said ports, a

- flexible diaphragm connected directly to said reciprocable means and means for maintaining fluid under pressure against the diaphragm,

wherebythe position of the reciprocable means is varied according to fluctuations in the pressure of said fluid.

'7. The combination with a gas compressor having pressure operated control devices for controlling the loading and unloading of the compressor, of a multi-port distributor valve comprising floating reciprocable means for controlling admission to or release of fluid from 'the' 'means is obtained.

8. The combination with a' gas compresso having pressure operated control devices for controlling the unloading and loading of the compressor, of a distributor valve including a barrel having ports disposed in spaced relation longitudinally oi the barrel communicating with the successive control devices, a piston mounted for reciprocation in the barrel to control the admission to or release of fluid from the ports, an inlet for introducing fluid under pressure into the barrel in spaced relation to the. piston, the barrel having a vent for releasing; fluid from the end of the barrel opposite the inlet, a flexible diaphragm associated with the piston, a motor for operated by the pressure within the intake or outlet to control flow oi fluid pressure line. a v

9. A distributor valve according to claim 2 in which the valve is an electrical valve controlled from the motor circuit operating the compressor. 10. The combination with a'gas compressor having pressure operated controldevices ior controlling the unloading and loading of the compressor, a distributor valve including a barrel having lines leading to the control devices and including a reciprocable piston controlling admission of pressure fluid to the lines of release therefrom, an inlet for introducing fluid under pressure into the barrel in spaced relation to the piston, the barrel having a vent for releasing fluid from the end or the barrel opposite the inlet, a conduit adapted to contain fluid-under pressure leading to the distributor valve to actuate the piston, and a pilot valve operatively connected with the pressure being controlled to control flowoi' fluid through the conduit.

through the fluid 11. The combination with a variable capacity ciprocable means for controlling admission to or release of fluid from the ports, means for normally resiliently forcing said reciprocable means in one direction, fluid pressure opposing means attached directly to the reciprocable means adapted to withstand fluid pressure from in one direction, fluid pressure opposing means the opposite direction over a relatively wide area, and a pilot valve having fluid communication with the gas compressoroperable by fluid pressure generated by the compressor for maintaining fluid under pressure against said pressure opposing means whereby the position of the reciprocable means is varied according to fluctuations in the pressure of said fluid.

12. The combination with a variable capacity gas compressor having pressure operated control devices for controlling the unloading and loading of the compressor, a multi-port distributor valve, lines leading from the ports to the control devices, the valve comprising fluid reciprocable means for controlling admission to or release of fluid from the ports, means for normally resiliently forcing said reciprocable means in one direction, and a pilot valve having fluid communication with the gas compressor 0perated by fluid pressure generated by the compressor for controlling reciprocation in the op-- posite direction to control flow of fluid through the conduit.

13. The combination with a gas compressor having pressure operated control devices for controlling the unloading and loading of the compressor, a multi-port distributor valve, lines leading from the ports to the control devices, a valve comprising floating reciprocable means for controlling admission to or release of fluid from the ports, means for normally resiliently forcing said reciprocable means in one direction, and pres sure responsive means including a pilot valve having fluid communication with the intake or outlet of the gas compressor operated by the pressure within thejintake or outlet for controlling reciprocation in the opposite direction, the last mentioned fluid being independent of the fluid being compressed by the compressor.

14. The combination with a variable capacity gas compressor having pressure operated control devices for controlling the unloading and loading of the compressor, a multi-port distributor valve, lines leading from the ports to the control devices, the valve'comprising floating reciprocable means for controlling admission to or release of fluid from the ports, means for normally resiliently forcing said reciprocable means attached directly to the reciprocable means adapted to withstand fluid pressure'from the op;-

posite direction over a relatively wide area, and

pressure responsive means including a pilot valve having fluid communication with the intake or outlet of the gas compressor'operated by the pressure within the intake or outlet to control compressor,- a distributor valve including a barrel having ports disposedin spaced relation longitudinally of 'the =barrel communicating with successively operable. control devices, a piston mounted for reciprocation within the barrel to control admissionfto' or release of fluid from the ports, an inlet for introducing fluid into the barrel in spaced relation to the piston, a flexiblediaphragm associated with the piston, means for passing fluid under pressure against the diaphragm whereby the position of the piston is varied, and stabilized control means operatively connected with the tube for automatically controlling the pressure of said fluid against the dia phragm according to fluctuations in the pressure within the tube.

16. The combination with a gas compressor having pressure operated control devices for controlling the unloading and loading of the compressor, the gas compressor being disposed in a tube which constitutes the inlet and outlet for the compressor, of a distributor valve including a barrel having ports disposed in spaced relation longitudinally of the barrel communicating with the successive control devices, a piston mounted for reciprocation in the barrel to control admission to or release of fluid from the ports, an inlet for introducing fluid under pressure into the barrel in spacedrel'ation to the piston, the barrel having a. vent for releasing fluid from the end of the barrel opposite the inlet, a flexible diaphragm associated with the piston, a fluid pressure conduit opening against one side only of the diaphragm'whereby ithe diaphragm is controlled, and pressure responsive means including a pilot valve in the fluid pressure conduit and a pressure controller connected to the tube and responsive to variations in pressure in the tube and operatively connected to the pilot valve to control the pilot valve, thevfluid in the fluid pressure conduit being independent of the fluid being compressed by the compressor. I

17. The combination with a gas compressor having pressure operated control devices for controlling the unloading and loading of the compressor, the gas compressor being disposed in a tube which constitutes the inlet and outlet from the compressor, of a distributor valve including a barrel having a line leading to the control devices and including a reciprocable piston controlling admission of fluid pressure to the line and release therefrom, an inlet for introducing fluid under pressureinto the barrel in spaced relation to the piston, the barrel having a vent sociated with the tube responsive to variations in pressure in the tube for actuating the valve.

vPAUL E. KUHL. 

